Physiology Flashcards
What are type 1 pneumocytes?
Single layer of alveoli wall. Aids diffusion
What are type 2 pneumocytes?
globous. secret fluid (surfactant) to moisten alveoli and prevent sticking together.
Where are sperms matured and learn to swim?
Epididymis
Function of seminal vesicles
provide sperms nutrients e.g. sugar for respiration
secrete mucus to protect sperm
Function of prostate
add alkali fluids to neutralise vaginal acid, mineral ions
Where is testosterone produced?
Interstitial cells
Where is FSH produced?
Anterior pituitary
What does testosterone, FSH, LH stimulate in spermatogenesis
FSH –> meiosis of primary spermatocyte
LH –> testosterone
Testosterone –> meiosis 2
Where is the origin of spermatogenesis
germinal epithelial
What is produced by type 2 pneumocytes?
Pulmonary surfactant
Which factors could cause emphysema?
a) air pollution
b) genetic predisposition
c) tobacco smoke
all above
Which organ in the human body secretes lipase, protease and amylase?
pancreas
In which process is surface area of key importance for humans?
a) reabsorption of glucose in the proximal convoluted tubule
b) release of surfactants by type 1 pneumocytes
c) display of antibodies by red blood cells
d) secretion of enzymes by villi of the small intestine
a
Which is the correct statement concerning HIV and AIDS?
a) all HIV patients have AIDS
b) HIV and AIDS are transmitted on the sex chromosomes
c) All AIDS patients have HIV
d) HIV and AIDS neutralize antibodies
c
What happens first when a neurotransmitter binds to a postsynaptic neuron?
a) ions diffuse
b) electrophoresis begins
c) Ca2+ channels open
d) repolarisation
a
Describe how the hormone leptin helps to prevent obesity
Produced in adipose tissue
(reject produced by pituitary)
target cells: hypothalamus
inhibits appetite
Explain the effect of neonicotinoid pesticides in insect synapses in the central nervous system
Bind to acetylcholine receptors Irreversible binding prevents acetylcholine binding Block transmission from central nervous system Cause paralysis
Outline the process of inspiration in humans
Volume of lungs increases
Pressure: decreases (air enters lungs due to increased pressure outside of body)
Diaphragm: contracts + downwards, pushing abdomen wall out. Abdomen wall relax
External intercostal muscles: contract, pulling ribcage upwards and outwards
Internal: relax (Expiration: Internal contracts, pulling ribcage inwards and downwards)
Describe the functions of valves in the mammalian heart
Prevent backflow
Open valves allow blood to flow thru
Opening and closing of valves control timing of blood flow during cardiac cycle
Closed semilunar valves allow ventricle to fill with blood/allow pressure in ventricles to rise
Valves open when pressure is higher upstream
Where does mitosis in oogenesis occur?
germinal epithelial
What is mitosis 1 in oogenesis stimulated by?
FSH
Which stage does meiosis 1 in oogenesis stop?
prophase 1
What does secondary oocyte produce? why is it produced?
1st polar body; cytoplasm divide unequally
What does meiosis 1 produced in oogenesis?
secondary oocyte + 1st polar body
Which stage does meiosis 2 stop in oogenesis?
metaphase 2
What’s the function of LH?
Ovulation
When’s meiosis 2 completed in oogenesis?
after fertilisation
What does empty follicles become after fertilisation of ovum?
corpus lutuem
What does corpus luteum produce?
progesterone
Describe the steps of fertilisation.
- Acrosome reaction: enzymes in sperm head digest zona pellucida
- plasma membrane of egg and sperm fuse
(Stimulates Ca2+ release in the egg; meiosis 2 completed) - Cortical reaction: Cortical granules fuse with egg plasma membrane
1, 2, 3 prevent polyspermy
Nucleus of sperm stays in the egg cytoplasm
What is a fertilised egg called?
zygote
What does a zygote develop into?
morula
What does morula develop into?
blastocyst
Where is the blastocyst implanted?
endometrium
When is HCG released?
After the implantation of blastocyst in the endometrium
What does HCG stimulates?
Stimulate corpus luteum in the ovary to secrete progesterone and estrogen
What do progesterone and estrogen inhibit?
LH, FSH
What is the function of progesterone?
To maintain the endometrium
What happens after progesterone is secreted during early pregnancy?
Blastocyst develops into fetus; placenta forms
What is a fetus surrounded by? What is it filled with?
amniotic sac, which is filled with amniotic fluid
What are the cells that separate maternal and fetal blood?
Placental barrier
What substances are exchanged in the umbilical arteries? How are they exchanged?
Carbon dioxide (diffusion)
Urea (diffusion)
water (osmosis)
Hormones
What substances are exchanged in the umbilical veins? How are they exchanged?
Oxygen (diffusion) Glucose (facilitated diffusion) Antibodies (endocytosis) Water (osmosis) Lipids Minerals, vitamins Hormones
What are estrogen and progesterone secreted by during pregnancy?
Corpus Luteum in the ovaries
Placenta
What is the muscular wall of uterus used during childbirth?
Myometrium
What does oxytocin stimulates?
The contraction of myometrium
How is positive feedback mediated when giving birth?
Contractions of myometrium are detected by stretch receptors, which signal the pituitary gland to increase oxytocin secretion.
What is oxytocin secreted by?
pituitary gland
What are the adaptations of the placenta?
Rich blood supply in fetus blood vessels
Few thin membranes give short diffusion path
Villi increase surface area of exchange
Placenta has many Rough endoplasmic reticulum and vesicles for production of HCG, progesterone, estrogen
What system is used by insects to remove nitrogenous waste and osmoregulation?
The Malpighian tubule system
What are osmoconformers?
Maintain an internal condition equal to the osmolarity of the environment
What are osmoregulators?
Regulate their body osmolarity, which always stay constant irrespective of the environment.
What is the function of cortex in the kidney?
ultrafiltration
selective reabsorption of blood contents
What is the function of medulla in the kidney?
Osmoregulation/reabsorption of water
What is the function of pelvis in the kidney?
Excretion: collecting ducts deliver urine to the pelvis to be passed on to the ureter
Labelling nephron: Which parts are there in the cortex and what are their functions?
Renal capsule: ultrafiltration
Glomerulus: deliver blood
Proximal convoluted tubule: selective reabsorption
Distal convoluted tubule: secretion of toxins to urine
Labelling nephron: Which parts are there in the medulla and what are their functions?
Loop of Henle: osmoregulation
Collecting duct: deliver urine to pelvis
What is the function of biceps? Is it a flexor or extensor?
Bends the arm. Flexor
What is the function of triceps? Is it a flexor or extensor?
Straightens the arm. Extensor
What is the function of humerus?
Anchors the muscle
What is the function of radius/Ulna?
Acts as forearm levers (radius for biceps; Ulna for triceps)
What is the function of cartilage?
absorbs shock and distributes load
What is the function of synovial fluid?
Lubrication, reduce friction in the joint
What is the function of joint capsule?
Seal the joint, contains synovial fluid
What is the function of tendons?
non-elastic tissue connecting muscle to bone
What is the function of ligaments?
non-elastic tissue connecting bone to bone
What does the myelination for nerve fibres allow for? What is its purpose?
saltatory conduction. Forces the action potential to jump from node to node.
What are nerve impulses?
Action potentials propagated along the axon of neurons.
What does action potential in a non-myelinated neuron activate?
depolarisation
What causes potential to increase during a nerve impulse passing along a non-myelinated neuron?
voltage-gated sodium-channels open. sodium ions entering the axon.
What happens in repolarisation?
potassium channels open and potassium ions diffuse out.
What does refractory period ensure?
one-way conduction
What returns axon to resting potential?
sodium-potassium pump
Outline the actions taken by the body to avoid infection when the skin is cut. (3)
Platelets release clotting factors clotting factors activate thrombin Thrombin converts fibrinogen to fibrin fibrin forms a clot that seals the cut phagocytes ingest pathogens
Identify two hydrolysis reactions that occur in the small intestine.
polysaccharides to disaccharides/monosaccharides
starch/glycogen to maltose
maltose to glucose
lactose to glucose and galactose
polypeptides to amino acids
triglycerides to glycerol and fatty acids
How does the composition of blood in the renal artery differ from that in the renal vein?
less urea and toxins less oxygen more carbon dioxide less salts and ions less water less glucose no change in proteins
What does urine contain?
urea, toxins, water, salts, ions
Describe the action of the heart in pumping blood. (5)
cardiac cycle
Sinoatrial node in the right atrium sends an electrical impulse to the atrium, then to ventricle, which trigger ventricle contraction
Atrium diastole: blood runs passively to the ventricles
Atrium systole: pumps remaining blood to left ventricle
Ventricle systole: atrioventricular valve closes; semilunar valve opens, blood pumped to aorta
Ventricle diastole: semilunar valves closes. Blood pumped from aorta to the body
What does the arrival of action potential in skeletal muscles cause?
release of Ca2+
Where is Ca2+ released during skeletal contraction?
from sarcoplasmic reticulum
Where does Ca2+ bind to during skeletal contraction?
troponin
What does the binding of Ca2+ to troponin cause?
Troponin and tropomyosin to move and expose binding sites on actin
How does myosin heads change shape?
energy released from ATP hydrolysis
What causes the breakage of cross bridges in skeletal contraction?
ATP hydrolysis
Define osmoregulators.
Organisms that maintain a constant internal solute concentration.
Define osmoconformers.
Organisms that have same internal solute concentration as the concentration of solutes in the environment.
What is the functional unit of kidneys?
Nephron
What is osmoregulation
the balance of salt and water in the body
What system do insect use to carry out osmoregulation? What does this system remove?
The Malpighian tubule system. removal of nitrogenous wastes.
What is Florey and Chain’s experiment?
to test penicillin on bacterial infections in eight mice
